A couple of things.....
First, having the guy cum in my mouth is the reason I like giving oral. That's part of MY reward for doing a good job. I'll admit it. I love the sensation and taste. And I've never had a guy complain when I swallowed his semen.
Secondly, I hate the taste of condoms. No matter WHAT you put on them to give them flavor.....they still taste awful.
No condoms in my mouth. If I have doubts about the guy I won't go down on him in the first place.
JMO.